The invention relates generally to humidification apparatus and more specifically to portable steam vaporizers intended for domestic use.
There are a number of different types of products used to increase the humidity in the home environment. Particularly during the winter season, the low humidity prevailing in most homes has led to the widespread use of some type of humidification means. Although in connection with forced air central heating there are often provided central humidification means in connection with the heating system, the more limited capacity portable humidifying appliances are in more widespread use. With respect to the portable humidifying appliances, they may be broken down broadly into two categories, one being the evaporation type and the other being the steam vaporizer type. The evaporation type humidifiers usually have had the larger water capacity and utilize belts, pumps, slingers or the like to increase the rate of evaporation of the water from the liquid to the vapor state. In general, the steam vaporizers have been of a more limited capacity and have been used often to achieve very high humidification levels as in the rooms of people with respiratory ailments and the like.
There are also humidifiers which use ultrasonic means to atomize water and thereby increase humidity. An example of such humidifiers is shown in Mizoguchi U.S. Pat. No. 4,640,804.
Examples of various prior art steam vaporizers are shown in the patents to Utley et al Pat. No. 2,369,623; Chelini Pat. No. 2,804,870; Parks, Sr. Pat. No. 2,810,167; Scott Pat. No. 3,152,240; Wunderlin Pat. No. 3,723,707; and Choe Pat. No. 4,604,246. All of these patents are characterized by disclosing steam type humidification means in which there is a reservoir or water supply of some type which supplies water in controlled amounts to a boiler or heating means which is intended to convert the water into a steam vapor. Of these prior art patents, the Chelini patent is an example of a non-portable type humidifier which is associated with a central heating system. It is, however, similar to the portable devices in that it has a water supply means which is connected by a conduit to a boiler in which a limited quantity of water is heated by electrical means to convert the water to steam.
There are many problems involved with the prior art steam vaporizers, primarily related to the rapid deterioration resulting from the problems with the heating elements and the impurities normally associated with boiling water. The mineral deposits which are left as the water boils away in the steam generating area tend to deteriorate the heating element or reduce its effectiveness and ultimately render the device inoperable.
Another problem often associated with prior art humidifiers is the danger to the user resulting from the high temperature of the steam used for humidification and the tendency for the steam to heat up the parts of the vaporizer whereby the user may be burned either by the heated parts on the appliance or the steam itself. Accordingly, it is desirable to provide means to avoid this overheating of the vaporizer parts and also to prevent the user from being exposed to the high temperature steam.